Created by: jinxing94

1） 问题： 对DynamicRNN输入时一个Lod_level=1的tensor, 输出的变量，使用sequence_pad报错。

paddle/fluid/framework.py", line 1058, in init self.desc.infer_shape(self.block.desc) paddle.fluid.core.EnforceNotMet: Enforce failed. Expected x_desc->GetLoDLevel() >= 1, but received x_desc->GetLoDLevel():0 < 1:1.

2） 版本 paddle paddle 1.4.1

3. 代码

class Model(object):
    def __init__(self, input_size, hidden_size):
        """
        init
        :param input_dim:
        :param output_dim:
        """
        self.x = fluid.layers.data(name="x", shape=[input_size], lod_level=1)
        self.hidden_size = hidden_size
        self.build()

    def build(self):
        """
        build
        :return:
        """
        self.x_proj = fluid.layers.fc(
            self.x, self.hidden_size * 3,
            param_attr=ParamAttr(name="gru.weight_ih_l0"),
            bias_attr=False)

        drnn = fluid.layers.DynamicRNN()
        with drnn.block():
            input = drnn.step_input(self.x_proj, level=0)
            hidden = drnn.memory(shape=[self.hidden_size])
            hidden_proj = fluid.layers.fc(
                hidden, self.hidden_size * 3,
                param_attr=ParamAttr(name="gru.weight_hh_l0"),
                bias_attr=False)

            i_r, i_i, i_n = fluid.layers.split(
                input, 3)
            h_r, h_i, h_n = fluid.layers.split(
                hidden_proj, 3)
            resetgate = fluid.layers.sigmoid(i_r + h_r)
            inputgate = fluid.layers.sigmoid(i_i + h_i)
            newgate = fluid.layers.tanh(i_n + resetgate * h_n)
            new_hidden = newgate + inputgate * (hidden - newgate)

            drnn.update_memory(hidden, new_hidden)  # set prev to hidden
            drnn.output(new_hidden)

        self.outputs = drnn()

        self.hidden = fluid.layers.sequence_last_step(self.outputs)

        pad_val = fluid.layers.assign(
            input=np.array([0.0], dtype=np.float32))
        self.outputs_pad, _ = fluid.layers.sequence_pad(
            self.outputs, pad_val)